You might recognize the shape of the large playplace inside Roquat's playroom. It looks a bit like the Ozzopotamus, a common toy for children in Oz. West uses Ozonium on her Ozzopotamus to bring it to life in Chapter 1 of Lost In Oz, entitled "Go Forth."
Smith tells West he can't paint after Langwidere used his creations as magical prisons. You might remember when Dorothy, Toto, and Glinda found themselves trapped in one such painting in Chapter 11 of Lost In Oz, entitled "11:11".